Liquid crystal displays (LCD) may be adversely affected by stress. An example includes the temporary picture distortion created when applying a force onto the glass substrate of a LCD TV screen or a LCD computer monitor. Picture distortion may become permanent if the stress imparted to the LCD permanently damages parts of the LCD, for example when the LCD device is dropped from a height. Permanent distortion may also result from a stress that constantly imparts a force or load on an LCD. In order to qualify for certain military applications, ruggedized LCD devices may be required to withstand threshold levels of stress and certain extreme environments. Also, ruggedized LCD devices may be required to have a seal in order to prevent external fluids from entering the device, which can adversely affect performance of the device.
Attempts to ruggedize LCD displays, often against high impact forces, have used laminated strengthening glass elements to give the LCD more strength. However, in some cases, these attempts have resulted in permanent distortion around the peripheral portion of the display in proximity of the mounting elements. Other efforts to ruggedize LCD displays, such as applying a hard adhesive on the periphery of the LCD to bind the LCD to a frame, have also resulted in similar distortion. Often, this distortion around the periphery of the display is referred to as window framing of the LCD. In addition, window framing may become further pronounced if the LCD device is subject to temperature extremes. Exposure to temperature extremes causes differential expansion to the different elements making up the device and may build up stress on the LCD case. This may also lead to warping of the case and bending stresses on the LCD.
Prior attempts to ruggedize the LCD include U.S. Pat. No. 6,871,138 B1 to Minelli, which discloses an electronic device that has a housing bonded to a touch panel with flexible adhesive that is intended to prevent fluid from reaching an enclosed display. Another attempt to ruggedize an LCD includes U.S. Pat. No. 5,606,438 to Margalit et al., which discloses the use of a LCD sandwich structure, where the LCD is bonded to two glass substrates through the use of an adhesive film. However, these prior attempts may suffer from issues related to the ability of the device to withstand stress and certain environmental conditions, as well as shielding against EMI.